Circular knitting machines



Jan. 28, 1969 Filed April 11. 1966 R. PEBERDY CIRCULAR KNITTING MACHINES Sheet ofB iNVENTOR ROMA/D pEBE/QDY ATTOQNEY Jan. 28, 1969 R. PEBERDY 3,423,962

CIRCULAR KNITTING MACHINES Filed April 11, 1966 Sheet 2' of 2 INVENTOR Pam/VD PEBE/PDY BY QEQUP M B\ 0% PNEY United States Patent Ofiice 159,781/ 65 U.S. Cl. 66121 Int. Cl. D041) 35/04, 9/10 3 Claims ABSTRACT OF THE DISCLOSURE A double-ended latch needle for use in a circular knitting machine of the opposed needle cylinder type, such needle having a stem and hooks at its opposite ends such hooks being curved with a small curvature of a radius substantially less than half the width of the hook and the hook ends continuing at an outward slant from the hooks and being engagea-ble with latches at positions inwardly from their extremities so as to provide a lead for engagement by a chisel end of a slider such that when the slider engages the needles it will engage a closed latch with certainty and open the same on transfer of the needle to the slider.

This invention is for improvements in or relating to circular knitting machines and has for an object to provide a needle construction by the aid of which improved reliability of the machine action can be secured in certain critical conditions.

The invention is more particularly concerned with machines of the opposed double needle cylinder type and the needles provided in such machines. These needles as is well known are double ended being equipped at each end with a hook and latch so that at different times a needle can be attached to a needle holding instrument or slider in the top cylinder and at other times to a similar slider in the bottom cylinder, the required motions to be imparted to the sliders and the needle being obtained by cams surrounding the cylinders. Each slider is provided with a needle-receiving recess on its inner side and a hook or clutch projecting into such recess for interengagement with the appropriate hook of the needle. The part of the slider extending along the outside of the recess serves to maintain the needle when engaged with the clutch in longitudinal alignment with the slider.

During the knitting procedure the knitting motions are imparted not only to the sliders carrying needles but also to empty sliders opposite them because their butts are still influenced by the cam tracks. Consequently at repeated times in the knitting cycle the top and bottom sliders are projected towards one another and the leading extremity of the empty slider passes in front of the hook of the needle. Despite very close manufacturing tolerances with which the knitting elements are constructed, such elements, particularly those used on fine gauge machines, are liable to give rise to diificulties when the machine is being run unless extreme accuracy is maintained in construction and assembly of the machine. One such difliculty may arise when the hook of the needle is required to pass behind the leading extremity of the opposite empty slider when, due to slight misalignment of the needles and sliders (arising from small variations in cylinder trick depth slight inaccuracy in relative positioning of the cylinders, excess clearance between the cams and cylinders as well as inaccuracy in the proportions of the needles and sliders themselves) the head of a needle may be caused to strike the end of the related empty slider instead of passing behind it, resulting in the needle being deflected outwardly. A similar condition may be brought about by an accidental build up of yarn around the needle. The invention has for 3,423,962 Patented Jan. 28, 1969 one of its objects to provide a needle construction wherein the risk of difficulties as just referred to may be largely or wholly avoided.

Previously to reduce the risk of diificulties as aforementioned it has been the practice to provide a chamfer on the extremities of sliders at their needle receiving ends so that if the needle should be in a slightly outwardly projected attitude it will be safely cammed behind the end of the empty slider as they overlap. However to suit certain types of knitting machines it has been found advantageous to employ an improved form of slider capable of opening the latch of the needle carried by the opposite slider and sliders of this type must have a chamfer of their leading extensions arranged in reverse to that just described. Such modified slider is thus more prone to deflect the needle in an undesired manner and it is particularly in relation to such sliders that the present invention is advantageous.

In accordance with the invention there is provided a double ended latch needle wherein the hook at each end has its curved part of less outside radius than half the width of the hook and has the extremity of the hook slanted outwardly from the curved end. Thereby the centre of the end of the hook is offset inwardly as compared with that of a normal hook and less likely to be deflected outwardly. Moreover the hook itself provides a cam slant which by engagement with the empty slider opposite to that carrying the needle will serve to cam the needle inwards if it is slightly misplaced in relation to the empty slider. Furthermore the shaping of the hook as just referred to presents an inner cam slant which on engaging a freshly fed yarn draws the yarn towards the back of the hook opening due to the movement of "the needle at that time thereby improving lie of the portion of the yarn extending from the feeder to the needles.

In a convenient construction the centre of the head or bent over end of the hook of the needle'is positioned so as to lie at about two-fifths of the distance measured outwardly from the back of the hook to the hook extremity. The slant of the back turned part of the hook may be at about 30 to the longitudinal centre line of the needle as seen in side view.

A convenient form of construction in accordance with the invention is illustrated by way of example in the accompanying drawings and will now be described with reference to the drawings in which:

FIGURE 1 is a cross-section view in elevation through part of the knitting head showing parts of top and bottom needle cylinders in cross-section, a double ended needle of improved form, a sinker and sinker bluff, sliders in said cylinders and cam boxes and cams for operating the sliders;

FIGURE 2 is an enlarged side view of part of an improved needle and part of an opposed slider, and

FIGURE 3 is a diagrammatic plan view of part of the needle circle showing in an exaggerated form the improved lie of a yarn being fed to the circle of needles.

The top cylinder is shown at 1 and bottom cylinder at 2 and they have vertical tricks 3 and 3a in which are housed respectively sliders 4 and 5. A needle 6 having hooks 6a and 6b is shown engaged with its top slider 4. The bottom latch 7 of the needle is shown being opened by a chisel point 8 formed on the bottom slider 5 which is being lifted by its butt 9 as it rides up a cam 10. In similar manner, the top slider 4 is provided with a chisel point 8a which is capable of opening the top latch 7a of the needle should the needle be working in the bottom cylinder.

To ensure that the chisel points 8 and 8a of the sliders 4 and 5 will penetrate between the latches 7, 7a and hooks 6a and 6b, the sliders are proportioned so that the tips 8 and 8a of their leading ends will always rub against 3 the hook tips (as illustrated in the case of the bottom sliders 5) even if in so doing the sliders may be tilted slightly away from the trick bottoms should the manufacturing tolerances so dictate. In other words the tolerances can never produce a gap between the hooks and slider tips.

The improved shape of the needle books can best be seen in the enlarged view FIGURE 2 of the hook 6a. Instead of the radius R of the bent over end of the book being equal to half H (the width of the hook) it is reduced to less than half, thus increasing the distance indicated at C from the tip of the hook to the centre of the radius R. The distance R is about equal to two-fifths of the distance H, and the bent over end of the hook indicated at 16 is slanted at an angle of about 30 to the longitudinal centre line of the needle as seen in side view in FIG. 2. The result of this is that should the needle be displaced outwardly due to such causes as previously mentioned, there is less possibility of the point of the slider passing behind the hook.

Although in the drawings the improved hook is shown on a particular needle i.e. one with a shaped stem, it can of course be applied to needles of other shape and in fact, if the type of knitting machine will function with such other shaped needles extra rigidity may be obtained by making the back of the needle straight.

In order to appreciate the improvement obtained in feeding yarn to empty needles of this improved type, it should be remembered that, when commencing knitting a new article, after having pressed off the previous one, because there are no previously knit loops to draw the yarn through and control the yarn as in normal knitting, the hooks of the needles must be relied upon to engage the yarn successively. Obviously the closer the yarn can be guided to the needle stems the more certain will be the feed. It is only possible to position the nose of a yarn feeder as close to the needles as is allowed by the latchguard which itself must be clear of the needle cylinder. Therefore it is important that such needle as it engages the yarn in its hook should urge the yarn in towards the rear of the hook opening so that the lie of the yarn is well within the tip of the hook of the next needle to take it while the latter is at a somewhat higher level. The necessity for this becomes greater should the make-up courses include a course or courses knitted on alternate needles only.

The improved needle shown in FIGS. 1 and 2 is not only more suitable for co-operating with an opposed slider but because the inside radius indicated at r in FIG. 2 is struck from the same centre as the outside radius R it is smaller than usual and therefore controls the yarn more precisely. Also its centre is now nearer to the back of the needle thus urging the yarn in towards the rear of the hook opening.

The diagrammatic plan view of part of the needle circle given in FIG. 3 shows the effect of the new needle on the lie on the yarn 11. The feeder nose is shown at 12 and the circle of needles at 13. The dotted line 14 which represents the lie of the yarn when using a normal needle provides an exaggerated comparison to illustrate the yarn position in relation to a needle 15 which is re quired to take the yarn, the full lines 11 showing that with the present improved needles the yarn is caused to be laid within the width of the hook of the needle 15 and closer to the back of the needle than would otherwise be the case.

What I claim is:

1. For a knitting machine, a double ended latch needle comprising a stem part, hooks at the ends of said stem part and latches associated with said hooks and pivoted to the stern part, each of said hooks having a curved part extending from a point in line with the back of the stem part, such curved part having externally a radius substantially less than half the width of the hook, and a hook top the outer periphery of which slants outwardly from the curved part to lie at an acute angle to the projecting extremity of the related latch when in the closed position.

2. A needle according to claim 1 wherein the center of curvature of the curved portion of each hook is positioned so as to lie at approximately two-fifths of the distance measured outwardly from the back of the stem portion to a line joining the extremities of the two hooks.

3. A needle according to claim 1 wherein the slant of the hook tip extending from the curved part of each hook is at an angle of substantially 30 to the line of the back of the needle as seen in side view.

References Cited UNITED STATES PATENTS 1,764,406 6/1930 Hohmann 66-121 1,769,319 7/1930 Stricker 66-12l XR 1,779,249 10/1930 Parlini 66121 XR 1,780,790 11/1930 Leavin et a1 66121 XR 1,824,445 9/1931 Parlini 66-l21 XR FOREIGN PATENTS I 301,349 11/1928 Great Britain.

457,017 5/1950 Italy.

WM. CARTER REYNOLDS, Primary Examiner.

US. Cl. X.R. 66-14 

